KahnBB6

iTrader: (5)

Hey guys,

I've searched high and low but I haven't found anyone specifically commenting on this configuration:

I want to know what city and highway fuel economy figures people are getting with a 1JZ-GTE VVT-i, R154 5-speed manual and 4.083:1 LSD rear axle combination. I'm only interested in stock or BPU tune. I'm not finding much on this but plenty on 1JZ non VVT-i's.

88supramki

You're not going to find a whole lot over here. Check out Soarer Central or an Aussie site they've had VVTi 1JZs much longer than us in the states.

JDMb16bEG6

Well I'm running a 1jz vvti with the w58 and stick diff, gas milange is just as or better then the 2jz ge but that's only out of boost, but who doesn't want to stay in boost? Everything is stick besides a front mount

4urxtc

iTrader: (2)

I have non-vvti auto 1jx and I get 25.8 on hwy trips if not 26mpg. So that should give you an idea of where you should be. You could be a little better than me with vvti though.

99SC42

iTrader: (44)

Guys the gear ratio in his dif and trans makes the difference so if you don't have the same combo as the OP your comment doesn't help him much.

KahnBB6

iTrader: (5)

^^ Thank you, this is very true. However, people who have swapped over their SC3 5-speeds would have similar gearing due to their stock 4.083 rear ends and it's only so different between the W58 and R154.

The difference is going to be in the variable valve timing and that stock CT15B single turbo making its peak torque at 2400rpm. 1JZ non-vvt's getting 24-26mpg highway is one thing but they don't have the (stock) low end that the VVT engines have that will affect city fuel economy. Also, automatic transmission economy will be different from a manual.

4urxtc

iTrader: (2)

I was just posting for reference not to say you woul be completely the same. Just figured it may help. Anyway good luck with your search.

KahnBB6

iTrader: (5)

Even though you aren't running a VVT-i, your info is useful. I apologize if I gave the impression that I didn't think so. I had a busy day at work and only replied once earlier. Yes, I'm curious specifically about the low end torque of the single turbo VVT-i affecting city economy but yours is also good contrast for anyone else who may benefit from reading this thread wishing to compare the two.

4urxtc

iTrader: (2)

It's all good in the hood. I really do hope to find out as well. Any info about fuel economy is good I think. I am going R154 first 1/4 of next year so knowing more about how the mpg would be nice. Vvti would be interesting as well. As you mentioned low end torque could make a difference.

DoomLight

iTrader: (3)

i wanna know what the miles per hours and tach read at with the 1jz+r154+4.08 LSD. vs the same thing with 3.92 sc400 diff.

i found a guy selling soarer lsd's cheap. i want to know how much higher will the rpms be at 60 to 80mph. right now im at 2200 rpms @ 80mph

KahnBB6

iTrader: (5)

You ought to be at roughly 2800rpm @ 70mph with a 4.08 ratio and a W58. The 5th gear is very slightly less aggressive with an R154 so you could be (guessing) at 2700rpm with that transmission.

My 5th gear cruising rpms have dropped very slightly since switching to an R154 but I am still on my custom 4.27+Torsen LSD rear.

If you have a source for a genuine Soarer Torsen LSD-- BUY IT. It should be a T-2 Torsen versus the twitchier T-1 Torsen found in Supra TT Automatic rear ends. We never got T-2 Torsens in the States.